A civil liberties group demanded answers from federal and state investigators who cleared a Boston FBI agent in the shooting last year of a friend of Tamerlan Tsarnaev, following a Globe report Wednesday on the agent’s troubled record as a police officer in California.

Hassan Shibly, executive director of the Council on American-Islamic Relations in Florida, said the Justice Department and a Florida prosecutor should have disclosed that agent Aaron McFarlane was the subject of police brutality lawsuits and internal affairs investigations and that he pleaded the Fifth Amendment during a police corruption trial in their March reports exonerating McFarlane in the shooting.

On May 22, 2013, the FBI agent shot and killed Ibragim Todashev after he allegedly confessed to helping Tsarnaev kill three men in Waltham in 2011. Todashev, a 27-year-old mixed martial arts fighter, allegedly attacked the agent and a Massachusetts State Police trooper after he sat down to write his confession, prompting the agent to shoot him.

“Did your office know about the allegations of abuse, corruption, and falsifying evidence against the FBI agent who shot Mr. Todashev?” Shibly said in a letter to the Florida prosecutor, Jeffrey L. Ashton, citing the Globe and his own investigation of the shooting. “If your office did not know about the agent’s history, how can the public trust the thoroughness and reliability of the investigation?”

AP/File

On May 22, 2013, the FBI agent shot and killed Ibragim Todashev after he allegedly confessed to helping Tsarnaev kill three men in Waltham in 2011.

Shibly sent similar letters to the Department of Justice’s Civil Rights Division, which also cleared McFarlane in March, and the FBI, asking the bureau if it had investigated McFarlane’s background at the Oakland Police Department in California before they hired him in 2008.

Justice Department spokeswoman Dena Iverson confirmed that the department received the council’s letter and is reviewing it. Ashton did not respond to requests for comment. The FBI declined to comment on the letter.

The FBI has refused to address McFarlane’s record, but in California court records, McFarlane denied any wrongdoing. He said he pleaded the Fifth during a police corruption trial in 2003, after a prosecutor suggested he had illegally falsified a police report, only to avoid being unfairly swept into the controversy.

McFarlane also denied beating anyone, as two lawsuits claimed, and said the plaintiffs were the aggressors. Former colleagues described McFarlane as a fine officer in one of the most crime-ridden cities in the United States.

Oakland police declined to reveal the outcome of its internal affairs investigations, saying the information is confidential.

McFarlane joined the Oakland police in 2000 and retired four years later at age 31, apparently for medical reasons, according to court records. He is collecting a pension of more than $52,000 a year, according to the state-run pension system.

McFarlane’s path from the troubled Oakland Police Department, which is under federal court oversight, to the FBI raised a number of questions Wednesday.

Daniel Pellissier, president of California Pension Reform, a Sacramento-based nonprofit advocating for California to better control pension costs, said McFarlane’s pension seemed high for such a short time on the force.

“I think that almost everyone would agree that a $52,000 pension for four years of work without some additional factor is ludicrous,” he said in a recent interview.

James J. Wedick, a former FBI agent who ran the public corruption squad in Sacramento, said it is risky to hire agents whose credibility has been questioned because doing so could weaken future cases.

“In a New York minute, his credibility is flushed down the toilet,” he said. “There should be a voice in the room that says, ‘We are creating a problem here that we may not be able to overcome later on.’ ”

Until the reports clearing the agent were released in March, the investigation had been shrouded in secrecy, generating criticism of the FBI. Much was known about Todashev’s violent criminal record, including an arrest the month he was killed for allegedly beating two men in a Florida parking lot. He was a friend of Tamerlan Tsarnaev, now dead, who with his younger brother Dzhokhar is suspected of carrying out last year’s Boston Marathon bombings.

But little was known about the only witnesses to his shooting, the agent and a Massachusetts state trooper, Curtis Cinelli. Another trooper, Joel Gagne, had also witnessed his alleged confession — the troopers said they recorded it — but had stepped outside to make a phone call shortly before the shooting.

The FBI and Ashton had refused to identify the agent and the troopers, citing concerns for their safety.

The Globe obtained the agent and the troopers’ names by removing improperly created redactions from an electronic copy of the Florida prosecutor’s report.

Todashev’s family and friends said the official investigations of the shooting failed to scrutinize the actions of the troopers before the shooting. Even if Todashev had attacked, they said, the agent and troopers could have tried to interrogate him at a secure location, possibly preventing the death of a key figure in the investigation into Tsarnaev.